Patent document 1 teaches a car air conditioner capable of auxiliary heating mode operation for supporting the heating capability of a water heater, wherein high pressure hot gas in a refrigerant cycle is led to an evaporator to heat air flowing through an air duct. ON/OFF operation of a compressor of the aforementioned air conditioner is controlled based on the detection signal of a pressure sensor for detecting pressure of the high pressure refrigerant in the refrigerant cycle.
Patent document 1: Japanese Patent Laid-Open Publication No. 5-223357